Studies of the aetiology of neonatal hepatitis and biliary atresia.

Aetiological factors were sought prospectively in 55 babies with extrahepatic biliary atresia, in 105 with neonatal hepatitis, and in 11 with intrahepatic biliary atresia, seen as a result of nearly complete ascertainment of these conditions in the State of Victoria between 1963 and 1974. In neonatal hepatitis infective causes were shown in 22 babies, galactosaemia in 6 and alpha1-antitrypsin deficiency in 8; familial occurrence was noted in 10 further babies and unrelated second diseases were present in 24 of the remaining 59 babies. The only clues to aetiology in extrahepatic biliary atresia were a suspicion of time-space clusters, a deficiency of affected babies born to young primiparous women, and an unexpected number of spontaneous abortions in the histories given by the mothers. Genetic factors appeared to be important in intrahepatic biliary atresia, but are not reported in detail. Hypotheses for the aetiology of neonatal hepatitis and of extrahepatic biliary atresia are presented. Both are considered syndromes with multiple causes. Recurrence risks in sibs are discussed, and are 1 in 7 for neonatal hepatitis of unknown cause, negligible in extrahepatic biliary atresia, and usually 1 in 2 or 1 in 4 in intrahepatic biliary atresia, depending upon the family history.